1. Field of the Invention
The invention generally relates to process or apparatus for road structure. More specifically, the invention relates to preformed modules or blocks of the portable mat type for pavement. Further, the invention relates to interfitting modules or blocks for pavement. A reusable mat provides a durable surface at tracking areas as typically found at construction sites. The mat configuration cleans the tires of trucks crossing the mat.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Regulatory bodies frequently implement tracking control at construction sites. Tracking control is used to prevent or reduce off-site vehicle tracking from entering a storm drain or watercourse. A first type of tracking control is to provide stabilized construction approaches. A stabilized construction approach is a constriction site ingress/egress point that is stabilized to reduce the tracking of mud and dirt onto public roads by construction vehicles. This type of construction approach is utilized at sites where dirt or mud can be tracked onto public roads; where the site is adjacent to water bodies; where poor soils are encountered; and where dust is a problem during dry weather conditions.
Tracking control measures include a variety of standards and specifications, including but not limited to limiting points of ingress/egress; limiting vehicle speeds; properly grading each ingress/egress to prevent runoff onto paved roads; routing runoff through sediment traps; and designing stabilized ingress/egress points to support the heaviest equipment that will use it. A common specification requires a gravel pad at ingress/egress points. A filter fabric under liner often is required to line the bottom of the pad. In one location, a gravel pad specification calls for 1 inch rough diameter, clean, well graded gravel and crushed rock, commonly known as Class 150 Riprap Bedding. Another location requires coarser aggregate, such as two to three inch stone. Another system requires four to six inch rock. In different locations, specifications are known to require gravel pads to be twelve to twenty feet wide, six to eight inches deep, and fifty to seventy feet long and sometimes longer, yet. Standards further require continued re-screening, washing, or application of additional rock to maintain effectiveness. In practice, heavy construction trucks and equipment almost inevitably will press the gravel into the underlying mud, requiring that the gravel pad be reestablished by application of fresh bedding rock. Reestablishing the gravel pad may be required any number of times, according to need.
In addition to requiring stabilized entrances and exits with gravel pads, tracking control measures further include street sweeping to prevent sediment from leaving the site; dust control during working hours; and cleaning trackout from paved surfaces each day or each shift. Other specifications are known to require that all materials spilled, dropped, washed, or tracked from vehicles onto roadways or into storm drains must be removed immediately. In practice, the method of removal may require special street cleaning equipment or manual labor. Some methods of cleaning a highway, such as the use of water trucks to remove materials dropped, washed, or tracked onto roadways are prohibited under any circumstances.
Where gravel pads are not adequate to control trackout, regulations may require resort to a second type of tracking control: installation of wheel shakers, which are steel plates with ribs or corrugations extending across the entrance/exit. Typically wheel shakers are installed in the stabilized construction approach at the full width of the gravel pad over a substantial length, such as twenty-four feet. Of course, these wheel shakers must be manufactured and installed to support all expected loads. The addition of wheel shakers to a gravel pad adds both the basic cost of the additional features and the associated costs of operation, inspection, maintenance and repair.
Where tracking pads and wheel shakers are inadequate to control trackout, regulations may require resort to a third type of tracking control: wheel washers. The contractor may have to install a wash rack or wash station where the wheels and undercarriages of exiting vehicles are washed. Wheel wash stations can be located at stabilized construction egress points to remove sediment from tires and under-carriages, and to prevent dirt, mud, and other sediment from being transported onto public highways. The wheel wash station should be installed on level ground, on a grid or pad of coarse aggregate, with a drainage ditch leading to an approved settling area or sediment trapping device. Where a wash rack is built, it often must be constructed of reinforced concrete with transverse concrete ribs for permitting drainage. A drainage underpass is required where water might pool on one side of the wash rack structure. The wash rack, like all other portions of a construction approach, must be built to withstand anticipated traffic loads. The wash rack, ditch, and sediment trapping device require frequent inspection, sediment removal, and repair to maintain system performance. A maintenance specification may simply provide that the entrance must be maintained in a condition that will prevent tracking or flow of mud onto public rights-of-way.
In addition, tire wash stations require a supply of wash water. Where available, the contractor might obtain water from existing water service connections or fire hydrants. Where local water supply is not available, the contractor may have to bring in temporary water storage tanks. When a wash rack is installed, a turnout or doublewide exit is needed to avoid having entering vehicles drive through the wash area.
The variety of standards and specifications that have been described, above, are examples taken from known regulations but are not exhaustive of all such requirements. These regulations indicate the seriousness of the trackout problem. Contractors are in need of improved technology that prevents or adequately controls trackout from construction sites. When a tracking pad can adequately control trackout, then the contractor may avoid having to install additional tracking control devices such as wheel shakers and tire washers. Similarly, the contractor may avoid having to construct and maintain ditches and sediment trapping devices. However, regardless of which types of tracking control are needed, it would be desirable for the contractor to have a stabilized construction entrance that is both durable and effective to remove mud from equipment tires. Similarly, it would be desirable for the contractor to be able to recover at least some of the costs of building and maintaining a stabilized construction entrance/exit.
Mats are known for their ability to serve as load supporting, good traction surfaces. Interlocking mat systems are used to form temporary roadways and to provide large area coverage with improved traction over soft and uneven ground. U.S. Pat. No. 5,807,021 to Aaron shows a ground cover mat with a high traction surface on both faces, to interact with both the underlying ground and with vehicles traveling over the mat. U.S. Pat. No. 6,695,527 shows an interlocking mat system for construction of load supporting surfaces providing good traction. These surfaces can be used as temporary roadways and equipment support surfaces. A company known as Newpark Resources, Inc., currently on the Internet at www.NewparkMats.com, provides a mat system that can cover a wide area and provide a supporting work surface. A company known as Pathway Mats, Inc., currently on the Internet at www.pathwaymats.com, provides a mat system that forms a portable platform, walkway or roadway for outdoor and indoor events and construction sites. While these known mats and mat systems are designed to provide a stable surface with good traction, they do not address the problem of controlling trackout from construction sites. Therefore, a mat system that controls trackout is desirable, but it is not yet known.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the method and apparatus of this invention may comprise the following.